While exercise can help prevent illness, sometimes you just can't avoid getting sick. Depending on your sickness, however, you might not have to stop exercising—web site HowStuffWorks shows us how to tell whether exercise will help or hurt your cold.

The best way to decide whether you should exercise is to employ what doctors call the "neck check." Feel free to go running if your cold is "above the neck." Above-the-neck symptoms include:

Runny nose

Nasal congestion

Sneezing

Sore throat

Doctors advise against proceeding with your exercise regimen if your symptoms are "below the neck," however. These symptoms include:

Chest congestion

Hacking cough

Nausea or upset stomach

High fever

Fatigue

Body and muscle aches

If your symtoms are below the neck—that is, if you have an infection in your chest or throat—you'll want to skip your exercise regimen for a few days while you get better. If it's just a simple head cold though, going for a mild jog won't hurt. In fact, it'll probably even help clear up your head a little bit (though I'd avoid going outside in the cold, or going to the gym and infecting everyone else—better to stay home and hit the free weights or the treadmill). Hit the link to read more, and if you get stuck with a cold, be sure to read our guide to effectively battling the common cold as well.